What fixed my stomach problem was switching from whole grain toast to oatmeal for breakfast. Also have yogurt with some really good probiotics. I think it was the soluble fiber and not having too much insoluble fiber. Seems to have straightened out my digestion, plus bonus of slowly losing weight without trying.
I tried a peppermint supplement and a stomach soothing tea with ginger but that didn’t work. Not saying it won’t work for you. Tea made with fresh ginger is very pleasant, regardless of efficacy.